GenomeNet

Database: PROSITE(DOC)
Entry: PDOC00511
LinkDB: PDOC00511
Original site: PDOC00511 
{PDOC00511}
{PS60032; GH9_1}
{PS00592; GH9_2}
{PS00698; GH9_3}
{BEGIN}
**************************************************************
* Glycosyl hydrolases family 9 (GH9) active sites signatures *
**************************************************************

The microbial degradation  of cellulose and  xylans requires  several types of
enzymes such as endoglucanases (EC 3.2.1.4),  cellobiohydrolases (EC 3.2.1.91)
(exoglucanases), or xylanases (EC 3.2.1.8) [1,2].  Fungi and bacteria produces
a spectrum of cellulolytic  enzymes (cellulases)  and  xylanases which, on the
basis of sequence similarities,  can be classified into families. One of these
families is known as the cellulase family E [3] or as  the glycosyl hydrolases
family 9  [4,E1].  The  enzymes  which  are  currently known to belong to this
family are  widely  distributed among bacteria, fungi, amoebozoa, invertebrate
metazoans, mosses, ferns, gymnosperms, and angiosperms:

 - Butyrivibrio fibrisolvens cellodextrinase 1 (ced1).
 - Cellulomonas fimi endoglucanases B (cenB) and C (cenC).
 - Clostridium cellulolyticum endoglucanase G (celCCG).
 - Clostridium cellulovorans endoglucanase C (engC).
 - Clostridium stercoararium endoglucanase Z (avicelase I) (celZ).
 - Clostridium thermocellum endoglucanases D (celD), F (celF) and I (celI).
 - Fibrobacter succinogenes endoglucanase A (endA).
 - Pseudomonas fluorescens endoglucanase A (celA).
 - Streptomyces reticuli endoglucanase 1 (cel1).
 - Thermomonospora fusca endoglucanase E-4 (celD).

 - Dictyostelium discoideum  spore  germination  specific endoglucanase 270-6.
   This slime mold enzyme may digest the spore cell wall  during  germination,
   to release the enclosed amoeba.
 - Endoglucanases  from  unicellular green microalgae, such as the unicellular
   alga Chlamydomonas  reinhardtii  or the colonial algae Gonium pectorale and
   Volvox carteri. Microalgae can utilize cellulose for growth in the absence/
   limitation of other C-sources by secreting endocellulases.
 - Endoglucanases from plants such as Avocado or French bean.  In  plants this
   enzyme may be involved in the fruit ripening process.
 - Invertebrate endoglucanases, secreted by salivary glands and the gut.

Three conserved  regions  in  these enzymes are centered on conserved residues
which have  been shown [5,6,7] to be important for the catalytic activity. The
first region  contains  the  characteristic DAGD motif, where the C-terminal D
acts as the catalytic base that extracts a proton from the nucleophilic water.
The second region contains an active site histidine and the third one contains
two catalytically  important residues: an aspartate and a glutamate. The fully
conserved nucleophilic  D  forms  H-bonds with the residues of the active-site
loop, comprising  of  regions  I and II, to bring it in the proper alignement.
The fully  conserved  E  acts as an acid that protonates the leaving group and
stabilizes the  positively-charged oxocarbonium transition-state. We have used
these three   regions   as   signature   patterns,   with  the  first  pattern
corresponding to  region  I,  the  second to region II and the third to region
III.

-Consensus pattern: [LVS]-x-[GK]-G-[WFYLM]-[YHF]-D-[ACGS]-G-[DSN]-x(2)-[KMR]-
                    [FAILY]-x-[FWYLQTV]-[APTNS]-[MLGAQS]
                    [The C-terminal D is an active site residue]
-Sequences known  to belong to this class detected by the pattern: ALL, except
 two partial sequences.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: [HLY]-[AILMV]-[FIL]-G-x-[NSTW]-x(2,4)-[SCTV]-[FY]-
                    [LIVMFY]-[SITV]-G-x(1,5)-[GSY]-x(2)-[AFPSTY]-[FLPSV]-x(2)-
                    [AILPQVM]-[HV]-[DHLS]-[KRS]
                    [H is an active site residue]
-Sequences known to belong to this class detected by the pattern: ALL.
 one partial sequence.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: [FYW]-x-D-x(4)-[FYW]-x(3)-E-x-[STA]-x(3)-N-[STA]
                    [D and E are active site residues]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 for Fibrobacter succinogenes endA whose sequence seems to be incorrect.
-Other sequence(s) detected in Swiss-Prot: 2.

-Expert(s) to contact by email:
           Siddiqui K.S.; ksiddiqui@kfupm.edu.sa
           Henrissat B.; bernie@afmb.cnrs-mrs.fr

-Last update: November 2018 / Text and old pattern revised; new pattern added.

[ 1] Beguin P.
     "Molecular biology of cellulose degradation."
     Annu. Rev. Microbiol. 44:219-248(1990).
     PubMed=2252383; DOI=10.1146/annurev.mi.44.100190.001251
[ 2] Gilkes N.R., Henrissat B., Kilburn D.G., Miller R.C. Jr., Warren R.A.J.
     "Domains in microbial beta-1, 4-glycanases: sequence conservation,
     function, and enzyme families."
     Microbiol. Rev. 55:303-315(1991).
     PubMed=1886523
[ 3] Henrissat B., Claeyssens M., Tomme P., Lemesle L., Mornon J.-P.
     "Cellulase families revealed by hydrophobic cluster analysis."
     Gene 81:83-95(1989).
     PubMed=2806912
[ 4] Henrissat B.
     "A classification of glycosyl hydrolases based on amino acid sequence
     similarities."
     Biochem. J. 280:309-316(1991).
     PubMed=1747104
[ 5] Tomme P., Chauvaux S., Beguin P., Millet J., Aubert J.-P., Claeyssens M.
     "Identification of a histidyl residue in the active center of
     endoglucanase D from Clostridium thermocellum."
     J. Biol. Chem. 266:10313-10318(1991).
     PubMed=2037583
[ 6] Tomme P., van Beeumen J., Claeyssens M.
     "Modification of catalytically important carboxy residues in
     endoglucanase D from Clostridium thermocellum."
     Biochem. J. 285:319-324(1992).
     PubMed=1637316
[ 7] Guerriero G., Sergeant K., Legay S., Hausman J.-F., Cauchie H.-M.,
     Ahmad I., Siddiqui K.S.
     "Novel Insights from Comparative In Silico Analysis of Green
     Microalgal Cellulases."
     Int. J. Mol. Sci. 19:0-0(2018).
     PubMed=29914107; DOI=10.3390/ijms19061782
[E1] https://www.uniprot.org/docs/glycosid
{END}
DBGET integrated database retrieval system